This invention pertains to the alignment of optical data signal components, and more particularly to the passive alignment of two optical alignment components through low cost, high precision, mass production techniques.
In optical signal data transmission, the need for accurate alignment is critical. Because optical fibers have such small dimensions the alignment of these fibers with other fibers, lenses or optical devices requires a high degree of precision. This high degree of precision results in an increased cost for the implementation of optical communication networks. When aligning optical network components, there are three main elements which must be precisely aligned. These include the active region of an opto-electronic device, such as a Vertical Cavity Surface Emitting Lasers (VCSELs) and PIN arrays, the optical lenses for focusing and directing the optical signals, and the optical fibers. Much work has been done on the alignment of the opto-electronic devices with lenses. However, there is no cost effective method for the alignment of the optical fibers with the lenses.
Because the diameter or width of optical fibers is so small, the alignment between fibers and optical devices requires alignment on the order of a few microns and usually less. Some devices and components have been developed to provide alignment between two optical fibers. One example is an elongated connector plug which allows two optical fibers to be inserted, one into each end, to align the two optical fibers. However, this is only effective between optical fibers, and the precision needed in generating the connector plug makes the use of such plugs expensive. Further, this is an impractical method of aligning optical fibers with lenses. Another method used to cooperate or align two or more fibers is a pin-in-hole method. This method requires a structure having two opposing plugs to be formed around terminal ends of at least two optical fibers to be aligned. The male plug includes at least two thin, long pins which protrude from the surface of the plug. The second plug, the female plug, includes at least two thin holes for receiving the pins. One example of the pin-in-hole method is the MT ferrule. This technique is effective for optical fiber alignment. But the alignment of fibers to lenses or opto-electronic devices is more complicated. The pin-in-hole technique for alignment of fibers with lenses or optical devices cannot be produced in a low-cost, mass-produced method. Generation of the protruding pin is costly and precise alignment if very difficult to achieve because the pin must extend out at exactly 90xc2x0 from the surface of the plug.
Opto-electronic modules require precise alignment of the optical devices to the lenses, and lenses to the fibers. Prior art alignment techniques required the devices to be powered, and then the lenses and fibers to be aligned to the device. This active alignment is costly and time consuming.
What is needed is a method and apparatus for accurately aligning optical fibers with lenses or optical devices which can be mass-produced, at low-cost, and still provide the precise alignment necessary. What is needed is an apparatus and method for passively aligning devices without the need for adjustments to the alignment components while providing alignment for a large number of components, thus eliminating the need to actively align each component.
In accordance with the teachings of this invention a novel method and structure is taught which provides alignment between a first optical alignment component and a second optical alignment component. The first optical alignment component includes at least one positioning aperture and at least one alignment element partially positioned within the positioning aperture. The second component includes at least one alignment channel configured to receive at least a portion of the alignment element providing alignment between the first and second optical alignment components. In one embodiment, the alignment component is a sphere. In one embodiment, the positioning aperture is a square V-shaped aperture.